Engines have utilized windage trays positioned in crankcases to modify flow dynamics in the crankcase. The use of windage trays is particularly prevalent in high performance engines, due to the propensity of high performance engines to be operated at high speeds for extended periods. However, the necessity of the windage tray varies based on engine operating conditions. During lower engine speeds the turbulence in the crankcase may not cause the oil aeration issues that are so prevalent at the high engine speeds. However, as the engine speed increases, the momentum of the crankcase flowfield and oil leakage via component bearings, perturb and impinge with high velocity on the free surface of the oil within the oil reservoir. Aeration is an inherent consequence of the oil interacting with the highly turbulent flowfield within the crankcase. A more quiescent oil free surface is one of the design goals of previous windage trays. However, during lower engine speeds oil aeration considerably decreases and may not pose a significant problem. Therefore, during lower engine speeds flow interruption created by the windage tray may not be needed. Furthermore, during low engine speeds the windage tray may interfere with oil draining. For instance, oil may impinge on surfaces of windage trays, thereby interfering with oil draining operation. Specifically, the amount and/or speed of oil returning to the oil pan may be reduced due to windage tray interference. Furthermore, some windage trays may also create losses in crankcase ventilation systems.
U.S. Pat. No. 6,019,071 discloses a windage tray with an oil flow path provided in the windage tray with integrated oil squirters directing oil towards the undersides of the engine pistons. However, the windage tray discloses in U.S. Pat. No. 6,019,071 suffers from the abovementioned problems of slow oil draining and crankcase ventilation losses.
Recognizing the problems described above and in an attempt to address at least some of the problems the inventors developed a method for operating an engine system. The method includes operating an engine to perform combustion, determining an engine speed and adjusting a flow profile of a plurality of deflectors in a windage tray positioned in a crankcase based on the engine speed. In this way, the flow profile of the windage tray may be dynamically adjusted to alter flow characteristics in the crankcase over a wide range of engine speeds. Consequently, the functionality of the windage tray can be varied to suit engine operating conditions, enabling the windage tray to reduce oil aeration during selected operating conditions while reducing windage tray flow interference during other operating conditions to increase oil draining, for instance.
In one example, the deflectors in the windage tray may be opened when the engine is operated below a threshold speed and closed when the engine is operated above the threshold speed. In this way, the windage tray acts to decrease crankcase turbulence around the lubricant reservoir, thereby decreasing oil aeration during high speed operation. Conversely, during lower speed engine operation the lubricant drainage interference is mitigated by opening the deflectors in the windage tray, thereby increasing the lubrication system efficiency.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.